Rail braces and rail brace assemblies are common railroad trackwork components, their primary function is to prevent rail rollover. They are most commonly used on railroad switches where the stock rail is not spiked, clipped or otherwise restrained on the gage (inside) side base. It is customary then that stock rails be braced on the field side to prevent rail rollover since the lateral forces generated by the passing locomotive and railcar wheels are sufficient to easily cause the rail to roll outwardly from track center. This rolling ultimately would allow the wheel to drop from the rail head causing the train to derail. Rail braces also are used in various locations where lateral forces are present, such as heavy curves on grades and in mountainous areas.
The evolution of rail braces began with one-piece rigid rail braces which were simply spiked into position up against the stock rail. These one-piece braces usually were forged from steel plate and were not adjustable. They commonly became loose after the passage of the first few trains.
Adjustable rail brace assemblies became preferred as they provided a means of retightening over time. Various types of adjustable rail brace assemblies used bolts to provide the tightening action. A good example of an adjustable, bolted rail brace assembly is the TOPNOTCHER adjustable rail brace developed by Pettibone Mulliken Corporation and still commercially available from Cleveland Track Material, Inc. of Cleveland, Ohio. These bolted designs provided adequate performance, a means of securing them in position and the ability to retighten. However, they were made of several components, were relatively expensive, and were time-consuming to install. Most importantly, they required maintenance in terms of retightening the nuts which always came loose due to vibration under load.
As train frequencies, tonnages and train speeds increased dramatically, and as track time required for installation and maintenance of the track components became much more restricted, the need for an improved rail brace assembly became apparent and necessary. In the 1980""s there was a general trend within the railroad industry to minimize the use of threaded fasteners due to limited track time and reduced track maintenance crews.
In response to these considerations, several different boltless adjustable rail brace assemblies have been developed and marketed. Most of these boltless brace assemblies use a resilient rail clip fastener to secure the components into position. The most popular assemblies provide improved performance for many applications but have inherent design drawbacks which limit their performance and which limit the types of locations and installations with which they can be used. These assemblies do not provide any positive vertical restraint (other than the toe load of the elastic fastener) to keep them secured tightly to the switch brace plate when subjected to any upward vertical force. Also, these assemblies cannot be adjusted easily to apply a desired lateral force to the stock rail. Yet additionally, installation of these assemblies is more difficult than desired.
With the advent of pre-assembled switch panels, concrete ties and automated track tamping, the limitations of the existing boltless rail brace designs are significant. The lifting action during loading and unloading of pre-assembled switch panels and the lifting action imparted during automated tamping, combined with the added weight of concrete ties, causes the brace assemblies to come loose and to be disengaged from the switch brace plates. This creates serious safety problems and new maintenance issues.
Despite the advances of recent boltless adjustable rail brace assemblies, there remains a need for a self-securing boltless rail brace assembly that provides positive vertical restraint. Preferably, any such rail brace assembly would be easy to manufacture, easy to assemble and disassemble, easy to apply any desired lateral force to the stock rail, and strong and reliable in operation.
In response to the foregoing concerns, the rail brace assembly of the present invention is adapted for use with a switch brace plate that supports a stock rail that extends along a longitudinal axis. The assembly according to the invention comprises a rail brace disposed adjacent the rail, the rail brace lying atop the brace plate, the rail brace having one or more rail-contacting walls, a wedge-contacting wall disposed opposite the rail-contacting walls, an upper wall, and an opening in the upper wall, the opening being located intermediate the rail-contacting surfaces and the wedge surface. The assembly includes a stop connected to the brace plate, the stop being spaced laterally from the rail. The brace plate is disposed between the stop and the rail. The stop has a wedge-contacting wall. A wedge is disposed between the stop and the rail brace, the wedge having a stop-contacting wall and a rail brace-contacting wall. When the wedge is moved longitudinally of the rail, it causes the rail brace and the stop to be moved relative to each other.
A clip housing having first and second ends is connected to the brace plate at a location between the rail and the wedge. The first end is connected to the brace plate and the second end extends through the opening in the upper wall. The second end has a bore extending therethrough. A resilient clip is provided to provide resistance to vertical and lateral movement of the rail brace. The clip has first and second legs that are joined by a laterally extending segment, a longitudinally extending segment, and a curved segment. The first leg being extends through the bore. Both the second leg and the longitudinally extending segment are in contact with the upper wall and thereby resist both vertical and lateral movement of the rail brace.
As will be discussed in detail hereafter, the invention provides solutions to the problems associated with prior devices. The various features and advantages of the invention will be apparent to those skilled in the art from a review of the accompanying specification, claims, and drawings.